support/scripts: handle paths with regex characters in per-package

Some constraints on a setup ended up with a plus sign in the path
for historical reasons and would then fail to match on the comparison
of the host/lib dir match. So, the =~ for bash can be augmented
with a double quote expansion to preserve the literal value of
the characters in the variable.

Example Path: /home/vagrant/test+buildroot/per-package

Signed-off-by: Charles Hardin <ckhardin@gmail.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>

support/scripts/check-host-rpath

@@ -98,7 +98,7 @@ check_elf_has_rpath() {
 	    # PER_PACKAGE_DIR and therefore ${perpackagedir} points to
 	    # a non-existent directory, and this check will always be
 	    # false.
-            [[ ${dir} =~ ${perpackagedir}/[^/]+/host/lib ]] && return 0
+            [[ ${dir} =~ "${perpackagedir}/"[^/]+/host/lib ]] && return 0
         done
     done < <( readelf -d "${file}"                                              \
               |sed -r -e '/.* \(R(UN)?PATH\) +Library r(un)?path: \[(.+)\]$/!d' \